Suspension Ideas and Questions

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
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humble sabot
27
Joined: 17 Feb 2007, 10:33

Re: Suspension Ideas and Questions

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in droop

-which you still get with shorter upper control arms to a point. The amount of suspension travel also comes in.
the four immutable forces:
static balance
dynamic balance
static imbalance
dynamic imbalance

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C09
0
Joined: 07 Jan 2011, 00:46

Re: Suspension Ideas and Questions

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humble sabot wrote:I find the premise of this conversation slightly odd.
I'll tell you why. As a rule the vast majority of cars with wishbone suspension have unequal lengths, and not only that i bet you'd have a bitch of a time trying to find one with longer wishbones on top (having the contact patch tuck under the car). I can't imagine a case where you'd actually want to add positive camber under roll or bump. In practice it comes out to a matter of degrees. The primary objective is to help to keep the tyre within its optimum camber range to maximise grip. F1 cars and some others often have a noticeable amount of negative camber at rest, especially on the front.

to respond to two other things:
I've noticed the same thing in f1, sometimes it looks very much like there is a real taper to the tyres, the outside sidewall being taller. I'm not certain if this is an optical illusion or the actual state of things. I'll try and find a pic.

and the other: f1 uses fairly the longest arms they can, the longer the arm the less change in angle.
I've got a lot to think about. Another thing I'd like to know about is if there are different ways to make the wheels turn: the geometry of the steering and how many different ways engineers can make the inner wheel turn more than the outer(in a turn) and the amount of difference. Also, what is the tightest practical turning radius for f1? What about the fore/aft placement of the axis where the axle/front wheel assembly turns?

I'm just full of questions here. Please teach me. F1 is so interesting to me.
Carbon fiber, aluminum, science, amazing statistics, you know how it goes.
"Those who dance are often thought mad by those who cannot hear the music."

"The only man who never makes a mistake is the man who never does anything."

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Suspension Ideas and Questions

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I think you are talking about caster and caster trail here ?
(shopping cart analogy)

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C09
0
Joined: 07 Jan 2011, 00:46

Re: Suspension Ideas and Questions

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marcush. wrote:I think you are talking about caster and caster trail here ?
(shopping cart analogy)
I dunno what I'm talking about, at least not the terminology of it. I would post some drawings, but it's not easy figuring this url stuff out. Do inform me of anything I'm wrong about.
"Those who dance are often thought mad by those who cannot hear the music."

"The only man who never makes a mistake is the man who never does anything."

Jersey Tom
Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Suspension Ideas and Questions

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Picking up a copy of Tune to Win would really be a good starting point
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

Caito
Caito
13
Joined: 16 Jun 2009, 05:30
Location: Switzerland

Re: Suspension Ideas and Questions

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Concerning camber in turning.

There's a "rule" that says: Don't you ever let your camber become positive.


But, why wouldn't you let your inner wheel get positive? Wouldnt that produce a higher lateral force?

Or at least keep it in 0(since a negative value would produce a force(camber thrust) opposing your turn)


Thanks!

bye
Come back 747, we miss you!!

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Suspension Ideas and Questions

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in circletrack (oval racing )positive inside camber is used.

Image
Image

riff_raff
riff_raff
132
Joined: 24 Dec 2004, 10:18

Re: Suspension Ideas and Questions

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marcush,

Oval track suspension set-ups are an anomaly. Oval track cars also use tire stagger (or at least they did a few years ago).

I haven't seen a modern F1 double wishbone suspension set-up, but many, many years ago when I worked in racing, the double wishbone suspensions were designed to give about 1/4deg of camber gain for each inch of bump travel. And as I recall, they never had positive camber, even in full droop.

riff_raff
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Suspension Ideas and Questions

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riff_raff wrote:marcush,

Oval track suspension set-ups are an anomaly. Oval track cars also use tire stagger (or at least they did a few years ago).

I haven't seen a modern F1 double wishbone suspension set-up, but many, many years ago when I worked in racing, the double wishbone suspensions were designed to give about 1/4deg of camber gain for each inch of bump travel. And as I recall, they never had positive camber, even in full droop.

riff_raff
sure.
Talking f1 you will not see much suspension travel anyways.and looking at the angling of the wishbones relative to the track surface it is obvious that neither camber gains nor track variation(scrub)over suspension is very high on their agenda.

Jersey Tom
Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Suspension Ideas and Questions

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riff_raff wrote:marcush,

Oval track suspension set-ups are an anomaly.
Not the word I would use.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

User avatar
mep
29
Joined: 11 Oct 2003, 15:48
Location: Germany

Re: Suspension Ideas and Questions

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riff_raff wrote:marcush,

Oval track suspension set-ups are an anomaly. Oval track cars also use tire stagger (or at least they did a few years ago).

I haven't seen a modern F1 double wishbone suspension set-up, but many, many years ago when I worked in racing, the double wishbone suspensions were designed to give about 1/4deg of camber gain for each inch of bump travel. And as I recall, they never had positive camber, even in full droop.

riff_raff
I expect thats because of the high negative chamber they run. A higher negative chamber on your loaded outside tyre just brings more than a positive one on your unloaded inside tyre. When you have around 4deg negative chamber (static) you just don't get the inside tyre positive during roll.

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C09
0
Joined: 07 Jan 2011, 00:46

Re: Suspension Ideas and Questions

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Thank you Riff Raff and Mep. I still don't clearly understand, but after a bit of thinking, I'll make sense of it.

Little off topic, but is Forza Motorsprt 3 a good way to learn about how to tune a car? About how accurate are the tuning options in game compared to real life?Thanx.
"Those who dance are often thought mad by those who cannot hear the music."

"The only man who never makes a mistake is the man who never does anything."

RacingManiac
RacingManiac
9
Joined: 22 Nov 2004, 02:29

Re: Suspension Ideas and Questions

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C09 wrote:
humble sabot wrote:I find the premise of this conversation slightly odd.
I'll tell you why. As a rule the vast majority of cars with wishbone suspension have unequal lengths, and not only that i bet you'd have a bitch of a time trying to find one with longer wishbones on top (having the contact patch tuck under the car). I can't imagine a case where you'd actually want to add positive camber under roll or bump. In practice it comes out to a matter of degrees. The primary objective is to help to keep the tyre within its optimum camber range to maximise grip. F1 cars and some others often have a noticeable amount of negative camber at rest, especially on the front.

to respond to two other things:
I've noticed the same thing in f1, sometimes it looks very much like there is a real taper to the tyres, the outside sidewall being taller. I'm not certain if this is an optical illusion or the actual state of things. I'll try and find a pic.

and the other: f1 uses fairly the longest arms they can, the longer the arm the less change in angle.
I've got a lot to think about. Another thing I'd like to know about is if there are different ways to make the wheels turn: the geometry of the steering and how many different ways engineers can make the inner wheel turn more than the outer(in a turn) and the amount of difference. Also, what is the tightest practical turning radius for f1? What about the fore/aft placement of the axis where the axle/front wheel assembly turns?

I'm just full of questions here. Please teach me. F1 is so interesting to me.
Carbon fiber, aluminum, science, amazing statistics, you know how it goes.
Like JT said, pick up a copy of Tune to Win, most of those are covered quite extensively to gain an understanding of it, without going full depth into the really math-y stuff...

As far as different rate of steering between inside and outside wheel, look up Ackermann....And there is a positive and anti version of it. And which to use again that depends on tire characteristic....

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C09
0
Joined: 07 Jan 2011, 00:46

Re: Suspension Ideas and Questions

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Is Tune to win a forum discussion here or a book? I've looked for it, even in the off topic forums, I can't find it.
"Those who dance are often thought mad by those who cannot hear the music."

"The only man who never makes a mistake is the man who never does anything."

User avatar
747heavy
24
Joined: 06 Jul 2010, 21:45

Re: Suspension Ideas and Questions

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"Make the suspension adjustable and they will adjust it wrong ......
look what they can do to a carburetor in just a few moments of stupidity with a screwdriver."
- Colin Chapman

“Simplicity is the ultimate sophistication.” - Leonardo da Vinci